You are correct in assuming, or actually knowing, that most tribes and cultures had taboos about homosexuality. Pagan religions were in the majority before Christianity came along, history proves that out. Pagan in my definition means any religion that wasn't based on the one true God. Christianity put an end to most pagan religions but not all of them.
These pagan cultures probably came to the conclusion if they wanted their people to survive, have children and continue their lineage, heterosexual acts provided a higher level of success in attaining that goal than homosexual acts did. Of course by my stating what used to be known as common sense I am now guilty of “hate speech.”